1. Field of the Invention
The present invention relates to a method for the manufacture of metal bands, and more particularly to bands made from an amorphous metal alloy by directing a stream of the molten metel against a quickly moving cooling surface where the metal solidifies, and a device for its implementation.
2. Description of the Prior Art
Methods which permit the manufacture of metal bands directly from the melt are known. Metal bands with an amorphous structure are manufactured by quenching a melt so quickly, typically having a cooling rate of approximately 10.sup.6 .degree. C./second, that solidification without crystallization occurs. The inner or outer surface of a rotating drum or of a continuously circulating belt can, for example, serve as cooling surfaces for the stream of molten metal. The thickness of the bands obtained in this manner can amount to a few hundreths of a millimeter with a width of a few millimeters (cf., for example, U.S. Pat. No. 905,758, German O.S. No. 2,606,581, German O.S. No. 2,719,710 and German O.S. No. 2,746,238).
It has become apparent however, that in the manufacture of such metal bands, particularly when in a continuous operation, the heat load on the cooling surface caused by the striking of greater amounts of the molten metal on the same circumferential line presents a great problem. There is the increased danger that the surface temperature of the cooling body is raised whereby the rate of cooling or the cooling velocity of the molten metal is reduced. An embrittlement of the band can then occur which can lead to fracturing.
Of course, one can provide a water cooling system in the interior of the cooling body for quicker dissipation of the heat. This, however, is a relatively expensive solution. Moreover, in the known devices, an increasing waviness of the cooling body surface occurs after a short operating time, which causes the formation of surface irregularities on the band surface such as depressions and increased roughness.